<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>

<body>
    <input type="button" value="按钮" id="bn">
    <script>
        function my$(id) {
            return document.getElementById(id);
        }
    //注册多个点击事件
    my$("bn").addEventListener("click",function (){
        alert("事件1");
    },false)
    my$("bn").addEventListener("click",function (){
        alert("事件2");
    },false)
    my$("bn").addEventListener("click",function (){
        alert("事件3");
    },false)
    </script>
</body>

</html>